1. Field of the Invention
The present invention concerns a sealing gasket for an obturator such as, for example, a ventilation regulator able to serve the sectioning, in ventilation circuits, of air cooling functioning at low pressure.
2. Description of the Prior Art
It is known, in a general way, such a ventilation regulator comprises a frame of machine welded sheet iron inside of which a shutter is pivotally mounted. Because of the considerable rate of leakage tolerated in the applications of which these regulators are usually the object, the "relative" fluid-tightness is obtained by metal-to-metal contact of the shutter on the frame, the obturation being obtained by a quarter-turn rotation starting from the open position and inversely.
It is established at present that in numerous types of application, the fluid-tightness of these regulators is judged insufficient, especially but not exclusively, for safety reasons.
This is particularly the case for the ventilative installations used in nuclear power plants. It is indeed indispensable, in the case of an accidental contamination of the flow of circulated air, to hermetically close the shutters so as to circumscribe the contamination, which is hardly possible with the shutters presently utilized.